(abbreviation, alt-of, initialism, slang) Initialism of one true pair (or pairing): the romantic pairing preferred by an author or reader of fan fiction.
Over Rico's shoulder, I see Claire biting her lip, wearing the look of a shipper watching her OTP interact. 2018, Britta Lundin, Ship It, unnumbered page:
Other common OTPs are Frodo/Sam and Aragorn/Legolas. 2007, Kristin Thompson, The Frodo Franchise: The Lord of the Rings and Modern Hollywood, page 179:
The 'shippers in the study asserted that they may enjoy reading stories about other 'ships, or stories without a 'ship […] but the stories they most enjoy are those about their OTP. 2013, Jennifer K. Stuller, Fan Phenomena: Buffy the Vampire Slayer, page 43:
(abbreviation, alt-of, initialism) Initialism of one-trick pony.